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采用水热法合成Bi_2Te_3粉体,将炭黑(CB)与其掺杂制备不同比例的碲化铋/炭黑(Bi_2Te_3/CB)复合材料,研究复合材料的热电性能。同时采用TGA、SEM、XRD等分析方法表征Bi_2Te_3/CB复合材料的结构,探究微观结构与热电性能的关系。研究发现:室温下,CB的引入使Bi_2Te_3/CB复合材料的热导率大大降低(0.5957 W/(m·K)降到0.0888 W/(m·K));随着Bi_2Te_3含量的增加,复合材料的电导率、热导率均增大,Seebeck系数先增加后降低;当Bi_2Te_3含量为88.9%时,在558℃烧结10min所得的Bi_2Te_3/CB复合材料室温下热电优值ZT最大(ZT=0.21)。虽然ZT值未能达到应用价值,但是CB的添加为改善Bi_2Te_3材料的热电性能,尤其在降低材料的热导率方面,提供了新方法和新思路。
The Bi 2 Te 3 powder was synthesized by hydrothermal method. The CB / Bi 2 Te 3 / CB composites were doped with different proportions of CB to study the thermoelectric properties of the composites. The structures of Bi 2 Te 3 / CB composites were characterized by TGA, SEM and XRD, and the relationship between microstructure and thermoelectric properties was also explored. The results show that the thermal conductivity of Bi 2 Te 3 / CB composites decreases greatly from 0.5957 W / (m · K) to 0.0888 W / (m · K) at room temperature with the addition of CB. With the increase of Bi 2 Te 3 content, When the content of Bi 2 Te 3 is 88.9%, the value of ZT is the largest (ZT = 0.21) at room temperature for Bi 2 Te 3 / CB composites obtained by sintering at 558 ℃ for 10 min, and the Seebeck coefficient increases first and then decreases. ). Although the value of ZT can not reach the application value, the addition of CB provides new methods and new ideas to improve the thermoelectric properties of Bi_2Te_3 materials, especially in reducing the thermal conductivity of materials.